Antibacterial properties of hop (Humulus lupulus) are known, particularly of strobile (female flowers) extract, used mainly as beer additive, which has flavoring and stabilizing effects, responsible for its bitter spicy taste. It is also known that the presence of beta-acids in strobile extracts provide antimicrobial properties, especially against Gram-positive bacteria and certain algae.
Phenylpropanol is known as a solvent for fragrances and odor masking agents.
Until now, no combinations with biocidal effect are known comprising both hop extract and phenylpropanol. The closest detected prior art was the international patent application WO2012175626, which relates to the treatment or prevention of scars, claiming an onion extract and liposomes further containing some optional ingredients, such as at least one preservative, such as phenylpropanol, among others, and/or at least one more active principle, such as hop extract, among many others. This document, which has an object completely different from the instant invention, neither mentions nor suggests the concomitant presence of hop extract and phenylpropanol, and also does not mention or suggest some effect issued from this combination.
It has been found, in accordance with the present invention, that non disclosed state of the art combinations of hop extract with phenylpropanol surprisingly present an important synergistic biocidal effect, which is as effective as of the one provided by known biocides.
According to the meaning used herein, the use of hop extract also includes the use of beta-acids per se, even if not contained in hop extract.